Note: Non-spirulina species, such as Anabaena species, Aphanizomenon species, and Microcystis species are possibly unsafe because they are usually harvested naturally and may be subject to contamination.

Background

The term spirulina refers to a large number of cyanobacteria or blue-green algae. Both Spirulina spp. and non-Spirulina spp. fall into the classification of cyanobacteria and include: Aphanizomenon spp., Microcystis spp., Nostoc spp., and Spirulina spp. Most commercial products contain Aphanizomenon flos-aquae, Sprirulina maxima, and/or Spirulina platensis. These algae are found in the warm, alkaline waters of the world, especially of Mexico and Central Africa. Spirulina spp. are most often grown under controlled conditions and are subject to less contamination than the non-spirulina species that are harvested naturally.

Spirulina is a rich source of nutrients, containing up to 70% protein, B-complex vitamins, phycocyanin, chlorophyll, beta-carotene, vitamin E, and numerous minerals. In fact, spirulina contains more beta-carotene than carrots. Spirulina has been used since ancient times as a source of nutrients and has been said to possess a variety of medical uses, including as an antioxidant, antiviral, antineoplastic, weight loss aid, and lipid-lowering agent. Preliminary data from animal studies demonstrate effectiveness for some conditions as well as safety, although human evidence is lacking. Based on available research, no recommendation can be made either for or against the use of spirulina for any indication.

Evidence

DISCLAIMER:
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Arsenic poisoning:
Spirulina extract plus zinc may be useful for the treatment of arsenic poisoning. Additional research is needed to confirm these findings.
Grade: C

Diabetes:
Preliminary study of people with type 2 diabetes mellitus reports that spirulina may reduce fasting blood sugar levels after two months of treatment. More research is needed before a firm conclusion can be drawn.
Grade: C

Eye disorders (blepharospasm):
Super blue-green algae may decrease eye lid spasms but additional high-quality research is necessary to make a recommendation.
Grade: C

High cholesterol:
In animal studies, spirulina has been found to lower blood cholesterol and triglyceride levels. Preliminary poor-quality studies in humans suggest a similar effect. Better research is needed before a firm conclusion can be drawn.
Grade: C

Malnutrition:
Spirulina has been studied as a food supplement in infant malnutrition but results have been mixed. More research is necessary in this area.
Grade: C

Oral leukoplakia (pre-cancerous mouth lesions):
Preliminary research has not clearly shown benefits of spirulina in the treatment of oral leukoplakia.
Grade: C

Weight loss:
Spirulina is a popular therapy for weight loss and is sometimes marketed as a "vitamin enriched" appetite suppressant. However, little scientific information is available on the effect of spirulina on weight loss in humans.
Grade: C

Chronic fatigue syndrome:
There is currently inadequate evidence to recommend the use of spirulina in chronic fatigue syndrome.
Grade: D